cos (2x) = cos x
2 cos^2 x -1 = cos x using the double angle formula
2 cos ^2 x -cos x -1 =0
factor
(2 cos x+1) ( cos x -1) = 0
using the zero product property
2 cos x+1 =0 cos x -1 =0
2 cos x = -1 cos x =1
cos x = -1/2 cos x=1
taking the arccos of each side
arccos cos x = arccos (-1/2) arccos cos x = arccos 1
x = 120 degrees x=-120 degrees x=0
remember you get 2 values ( 2nd and 3rd quadrant)
these are the principal values
now we need to add 360
x = 120+ 360n x=-120+ 360n x = 0 + 360n where n is an integer
Answer:
carnation $2.50; rose $3.00
Step-by-step explanation:
Let c = price of 1 carnation.
Let r = price of 1 rose.
3c + 5r = 22.5
3c + 2r = 13.50
Subtract the se3cond equation from the first equation.
3r = 9
r = 3
Now substitute r = 3 in the first equation and solve for c.
3c + 5r = 22.5
3c + 5(3) = 22.5
3c = 7.5
c = 2.5
Answer: carnation $2.50; rose $3.00
Answer:
<em>YESSS</em><em>!</em><em>!</em><em>!</em><em> </em>
HOPE IT HELPED
Answer:12/1
Step-by-step explanation: